FOOD SLEUTHS LINK MYSTERY ILLNESSES TO POTATO SALAD

The calls began a day or two after one of the biggest graduation weekends of the season.

Hundreds of people phoned doctors and health officials to report persistent flu-like symptoms. And most said they had gone to parties in the south and southwest suburbs during the weekend of June 6.

In all, 1,800 people got sick that weekend, creating what officials believe was one of Illinois' largest outbreaks of food poisoning.

The reports of fever, nausea and headaches, among other symptoms, prompted days of painstaking detective work by health officials, who interviewed sick people and restaurant employees and took dozens of samples from afflicted people.

The sleuthing paid off. On Tuesday, a spokesman for the Cook County Department of Public Health said officials had determined that the victims fell ill 36 to 48 hours after eating potato salad prepared at Iwans Deli and Catering, a popular restaurant in Orland Park.

"The more they ate, the sicker they became," said spokesman Sean McDermott.

The caterer has not been formally linked to the outbreak, McDermott said, and lab results were still pending, but the Iwans potato salad is "the most likely suspect."

The final determination will be made within a week, when lab results are complete.

Cook County health department officials believe that in Orland Park, contamination occurred during the preparation of potato salad because, "If the products used to make the salad came into the shop contaminated, we would have seen outbreaks at establishments involved with the vendors," McDermott said.

Possible causes include "something that happened during preparation, such as improper employee hand-washing," McDermott said. "We don't have anything conclusive until the results come back, but the common denominator is Iwans."

A similar sleuthing process began after a recent national salmonella outbreak, which was linked to a brand of toasted oat cereals. Malt-O-Meal Inc. recalled up to 3 million pounds of cereal June 5 as a precaution after the cereal was linked to salmonella infections in 12 states, including Illinois.

The outbreaks add fuel to a national discussion about food safety, which has prompted health officials to be more vigilant in getting the word out about proper food preparation and cleanup.

Across the state, the detective work begins with interviews of victims whenever two or more cases of food poisoning are reported in the same area.

The largest food-poisoning outbreak in the state was in 1985, when 16,000 salmonella cases were traced to contaminated milk, McDermott said.

In the toasted oats case, officials suspected a common food source was behind the illnesses because all of the victims were infected with the same relatively rare strain of the salmonella bacteria, said P.J. Burtle-McCredie, spokeswoman for the Illinois Department of Public Health.

Then the problem was to identify the source of the bacteria.

Once a cluster of cases is flagged, officials begin to interview the victims, asking them what they had eaten in recent days and ask where the products were bought.

Based on the questionnaires, investigators try to determine common links.

Depending on the nature and scope of the outbreak, state and federal agencies may be called to assist in the investigation. Already the Orland Park investigation has been widened to include laboratory support from the federal Centers for Disease Control and the Illinois Department of Public Health.

Investigators also interview people who consumed the same meal but did not become ill, so various food items can be eliminated from the "suspect" list.

Finally, officials can come up with the likely food culprit and identify the bacteria that survived the usual food-handling precautions.

In the most recent case, investigators have found neither traces of salmonella nor a particularly vicious strain of E. coli, McDermott said.

Instead, state and federal officials are trying to determine whether the bacteria was a less dangerous form of E. coli, McDermott said.

"That's what we're looking at right now, the other types of E. coli," he said.

In 1993, the more destructive strain of the E. coli bacteria killed three children and made more than 400 people sick after they ate undercooked hamburgers at a fast-food chain in Washington state.

Iwans was closed last week by mutual agreement while officials conduct the food-poisoning investigation.

The restaurant will not be allowed to reopen until the contamination source is identified and resolved, said Orland Park spokeswoman Jodi Marneris.

The business has always passed its quarterly village inspections, Marneris said.

Iwans' owner, Matthew Iwan, said Tuesday he is as concerned as officials about pinpointing what might have gone wrong.

"We are very broken up about it," said Iwan, adding that although he and his staff have been working closely with authorities, he had not been told the suspect food item had been tentatively identified.

"We've been in business for 14 years and have never had a problem."

McDermott said most people who notified health officials about eating the catered food have recovered, but he urged anyone who still suffered from food-poisoning symptoms to contact their doctor.